Causes and consequences of climate change
Human activity has influenced global climate systems by
greatly increasing atmospheric concentrations of greenhouse
gases, primarily carbon dioxide (CO2), methane (CH4),
nitrous oxide (N2O) and tropospheric ozone (O3).
Why should a few degrees of warming be
a cause for concern?
The International Panel on
Climate Change (IPCC) reports that 23 global climate models
predict world temperatures will rise by 2 to 12
degrees Farenheit by the end of the century. Climate
modelers conclude there is a 66 percent chance that the
increase by 2100 will be between 3.6 and 8.1 degrees.
Read the IPCC 2007 Climate Change summary for policy makers.
These changes may lead to a number of
potentially serious consequences. For example, mid-and
high-latitude regions including much of the United States,
Europe, and Asia, could experience an increase in the
incidence of heat waves, floods and droughts as the global
climate changes. The impacts of such extreme events on
human welfare as well as natural ecosystems could be
significant.
For Colorado, global warming will likely mean diminished
snow pack, increased drought, more insect outbreaks in
forests, an earlier and longer wildfire season, reduced
habitat for native species, and less economic
growth in certain industries, such as farming and
skiing. The
IPCC reports that the Rocky Mountains will probably see
less snow and a shorter snow season as the century wears on.
Although global-warming-caused increases in water vapor
could result in increased precipitation, higher temperatures
will probably create a net drier climate. Local temperatures
may average 7 degrees warmer than current temperatures,
according to Linda Mearns, a National Center for Atmospheric
Research senior scientist.
Criticism of Climate Change
Many skeptics of climate change claim
climate change is a result of a natural cycling of the sun
that flexes over thousands of years. However, the
2007 IPCC
climate change summary includes proven data that the solar factor
is one half of what was originally assumed. The report
states, "It is very unlikely that climate changes of at
least the seven centuries prior to 1950 were due to
variability generated within the climate system alone."
Local governments think globally, act locally
Boulder County and other local
governments are not waiting for Federal action to reduce
harmful emissions. The
City of Boulder's Office of Environmental Affairs has
created a
Climate Action Plan, and in November 2006, Boulder
residents approved a
Climate Action Plan tax - the first in the country - to fund the necessary programs
and changes to implement the Plan.
In 2005, the Boulder County
Commissioners adopted two
Sustainability resolutions as
first steps to take an active role in reducing climate
change and harmful emissions and pollutants. In accordance
with the resolutions, Boulder County has taken an inventory
of its greenhouse gas emissions (GHG) to determine the
source and quantity of emissions and thus set benchmarks and
goals for emission reductions. The inventory has revealed
that it is impossible to reach Boulder County's original
goal of meeting the Kyoto Protocol standard of reducing
greenhouse gas emissions to 7 percent below estimated
emissions within the County in 1990. However, Boulder County
is working to revise goals and objectives to meet the most
aggressive attainable standards.
To affect climate change, we all must do our part to reduce greenhouse gas
emissions. Boulder County is committed to finding ways to
meet our growing energy demand while protecting the
environment and stimulating the economy. We are also
committed to making sure that our residents have the
information and resources necessary to use less energy, save
money and make the best possible energy choices. This
includes knowing how to pick the most energy efficient
products and appliances, improve the efficiency of homes and
commercial buildings, use alternative transportation and
much more.
Emissions sources in the United States
Where do greenhouse gases come from? It is a
well-researched fact that the combustion of fossil fuels
releases greenhouse gases (GHG), namely carbon dioxide (CO2),
into the atmosphere, causing global surface temperatures to
increase.
Methane and
nitrous oxide are often associated with livestock and
agriculture. The U.S. Department of Energy provides the
following data regarding carbon dioxide emissions:
Residential Sector
Residential carbon
dioxide emissions represented 21 percent of U.S.
energy-related carbon dioxide emissions in 2004. The
residential sector’s pro-rated share of electric power
sector emissions accounts for more than two-thirds of all
emissions in the residential sector. Natural gas accounted
for 22 percent, and petroleum (mainly distillate fuel oil)
represented 8.9 percent.
Commercial Sector
Commercial sector carbon dioxide emissions accounted for about 17 percent of total energy-related
carbon dioxide emissions in 2004, of which 78 percent is
the sector’s pro-rated share of electricity-related
emissions. Natural gas contributes 16 percent and petroleum
6 percent of the sector’s emissions.
Industrial Sector
Industrial sector emissions
accounted for 29 percent of total U.S. energy-related
carbon dioxide emissions in 2004. In terms of fuel
shares, electricity consumption was responsible for 38
percent of total industrial sector emissions, natural gas
for 26 percent, petroleum for 26 percent, and coal for 10
percent.
Transportation Sector
Carbon dioxide emissions from the transportation sector, accounted for 33 percent of total U.S.
energy-related carbon dioxide emissions in 2004. Almost
all (98 percent) of transportation sector emissions result
from the consumption of petroleum products: motor gasoline,
at 60 percent of total transportation sector emissions;
middle distillates (diesel fuel) at 22 percent; jet fuel at
12 percent of the total; and residual oil (i.e., heavy fuel
oil, largely for maritime use) at 2.8 percent of the
sector’s total emissions. Motor gasoline is used primarily
in automobiles and light trucks, and middle distillates are
used in heavy trucks, locomotives, and ships.
For more information, visit: the U.S. Energy Information
Administration at
http://www.eia.doe.gov/.
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There is increasing scientific evidence
that carbon dioxide and other greenhouse
gases released into the atmosphere are exerting a profound
effect on the Earth’s climate, increasing extreme weather events, changing rainfall and crop
productivity patterns, and fueling the migration of infectious diseases.